Microspore spherical or oval, with or without a bladder-like extension of the exine, containing a prothallus of two or more cells, one of which produces two non-motile or motile male cells.
- Germinating pollengrain of Epilobium (highly mag.) bearing a pollen-tube s; e, exine; intine; abc, the three spots where the exine is thicker in anticipation of the formation of the pollen-tube developed in this case at a.
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